1. Field of the Invention
This invention relates to a method for regenerating a thermosensitive transfer recording medium wherein a thermosensitive transfer recording medium can be repeatedly used by supplement of inks to the medium. The invention also relates to a thermosensitive transfer recording medium which is adapted for carrying out the regeneration method, and also to a regeneration apparatus and a thermosensitive transfer recording apparatus.
2. Description of the Related Art
Thermosensitive transfer recording methods have been hitherto widely used wherein a material to be transferred such as a printing sheet and a thermosensitive transfer recording medium are superposed, and the medium is selectively heated according to image signals by use of heating means such as a thermal head, a laser beam or the like thereby transferring a dye from the recording medium to the material to be transferred to print the image. The thermosensitive transfer recording medium are thrown away. From the standpoints of economy and ecology, there is a social demand for regenerating the wasted thermosensitive transfer recording medium for repeated use.
The manner of improving the utilization efficiency of the recording medium may be broadly classified into two categories. One category includes a method wherein a dye layer of the medium is regenerated and repeatedly used such as in a dye layer regeneration method and in a method using a multiple mode dye layer arrangement. The other includes a method of effectively utilizing the recording medium such as a relative speed method. The dye layer regeneration method is a method wherein a thermosensitive transfer recording medium, which is used in thermosensitive transfer recording systems of the thermal fusion type (wherein a dye layer is thermally fused and transferred to a material to be transferred thereby forming an image), is regenerated for repeated used. For the regeneration, the thermosensitive transfer recording medium is arranged in the form of an endless belt and the dye layer of the recording medium which has been consumed by the transfer is re-formed by application of a thermally fusible ink such as set forth in Japanese Patent Publication Nos. 49-26245 and 59-16932. The method making use of a multiple mode dye layer arrangement is also applicable to the thermal fusion thermosensitive transfer recording systems, in which a dye layer of an ink sheet is formed by impregnating a thermally fusible ink in a porous network structure layer. By this, when the ink in the surface of the ink sheet has been consumed, the ink is exuded from the inside to the surface. This permits repeated transfer operations (Ozawa and Shimizu, National Meeting of the Electronic Communication Society, 1236(1983)). The relative speed method is a kind of thermosensitive transfer recording method using sublimable dyes wherein an ink sheet is fed at a relative speed different from that of a material to be transferred, thereby improving repeated recording properties of the ink sheet. This method allows the dye layer to be transferred several times (Taguchi et al, Journal of the Electrophotographic Society, Vol. 24, No. 3, p. 17(1985)).
Among the conventional methods of improving the utilization efficiency of the thermosensitive transfer recording medium, the dye layer regeneration method and the method using the multiple-mode dye layer arrangement have difficulties in the uniform reformation of the dye layer surface of the thermosensitive transfer recording medium. In the dye layer regeneration method, the dye is supplemented by a wet process which requires organic solvents. This will prevent the supplemental mechanism and the maintenance from being simplified. With the method using the multiple mode dye layer arrangement, any dye is not supplemented from outside to the once formed dye layer, ensuring only several times of repetitions of the recording cycle using the ink sheet. Thus, a greater number of the ink transfer cycles is not possible. This is the reason why these methods have never been put into practice. On the other hand, the the relative speed method has the problem that the mechanism for changing the relative speed between the material to be transferred and the ink sheet becomes complicated. In this method, the dye is not supplemented from outside and the ink sheet is used only in several repeated recording cycles. Thus, a greater number of transfer cycles are not possible. The relative speed method has not been reduced into practice yet.